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        // var result = "hello".replace(/(?=l)/g, '#');
        // console.log(result);

        // var arr=[12,2,3,4,5,6];
        // var str='同学1，同学2，同学3，同学4';
        //  var newstr=str.replace(/，同学4$/,'和同学4');
        //  console.log(newstr);


        var e=/^\d+[^12345]\.(abc|bfe)$/;
        document.write(e.test('2988.abc')+'<br/>')
        var ee=/^\S123$/;
        document.write(ee.test('f123'))
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